Show services discovered by site agents as suggested targets

Stores the sanitised list per site, serves it at /sites/{id}/discovered and adds
it to the target picker. Needs a Reef release containing model.DiscoveredService.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

server.go

@@ -130,6 +130,7 @@ func (s *Server) Handler() http.Handler {
 	mux.HandleFunc("PUT /api/orgs/{org}/sites/{id}", s.withOrg(true, s.putSite))
 	mux.HandleFunc("DELETE /api/orgs/{org}/sites/{id}", s.withOrg(true, s.deleteSite))
 	mux.HandleFunc("GET /api/orgs/{org}/sites/{id}/containers", s.withOrg(true, s.siteContainers))
+	mux.HandleFunc("GET /api/orgs/{org}/sites/{id}/discovered", s.withOrg(true, s.siteDiscovered))
 	mux.HandleFunc("POST /api/orgs/{org}/domains", s.withOrg(true, s.addDomain))
 	mux.HandleFunc("DELETE /api/orgs/{org}/domains/{id}", s.withOrg(true, s.deleteDomain))
 	mux.HandleFunc("POST /api/orgs/{org}/domains/{id}/check", s.withOrg(true, s.checkDomain))